Process of manufacturing flint or like pyrophoric material in extrusion presses



United States P ent PROCESS OF MAN FACTURINGLFLINT QR LIKE I PYROPHORICMATERIAL IN EXTRUSION PRESSES Walter Bungardt, Essen, Germany, assignorto Th. Goldschmidt A.-G. Chemische Fabriken, Essen, Germany, a Germancorporation No Drawing. Application January 23!, 1953, Serial No.332,989

This invention relates to. the manufacture offiint or like pyrophoricmaterial, in particular-gin rod formation as disclosed in mycopendingapplication Ser. No. 117,069, filed September 21, 1949, and nowU. SL'Patent No. 2,660,301.

Experiments have shown that if cerium-iron-alloys melted at atemperature between 1000 and 1200 C. are cast in molds of cast ironwhich are preheated to a temperature of approximately 600 to 700 C., thethus obtained cast ingots may be used as starting material for themanufacture of hints or like pyrophoric material in extrusion presses.As a source of cerium there may be employed misch metal whichcontains/the metals of the rare. earth group as main constituents: andhas. a. cerium content ofabout 45-55%.

Such material can then be subjectedto the; action of anv extrusion pressat temperatures ranging between 400 to 500 C. in order to obtain flintand like rods which are subsequently cut to conventional. lengths,asrequired by the trade.

Depending upon the iron content of such alloys and depending upon thequality of the misch metal to be employed', shaping. through extrusionpresses necessitates quite different maximum press powers. If the ironcontent: increasessuch. press. power must generally be considerablyincreased. In view of the different degrees of impurities which may bepresent in the misch metal compounds to be worked upon- (said degreesdepending upon the chemical composition of theore employed), this presspower may be considerably varied or influenced. The press power becomeshigher the greater the degree of impurity which is present in the mischmetal.

Extensive experiments have shown that it is possible to add or to admixto the misch metal-iron alloys such types of metals which have the sameor a greater heat of formation when combined with oxygen (unit:gram-atom oxygen, than that of the cerium, so that the maximum presspower required for the extrusion process may be considerably reduced.

This improving effect of the aforesaid metal additions is generallybased on two conditions. In order to reduce the press power duringextrusion formation under otherwise substantially equal outer pressureconditions, it appears necessary to reduce the inner friction of theparticles within the ingot to be extruded. This can be achieved byeliminating from the ingot disturbing impurities, such as oxides or,possibly, nitrites, hydrides, carbides and similar impurities which areeither contained in the misch metal itself or are admixed thereto byotherwise usual additions, such as for instance, iron. In the presenceof certain definite metallic element additions and through substantiallypure alloy effect a further reduction of the inner friction of the metalparticles may be obtained, whereby the extrusion press power will bedecreased.

In accordance with the present invention the pyrophoric mischmetal-iromalloys with an iron content of 4.5% to 401% are alloyed, inorder to reduce the press power needed for carrying out the extrusion,with such metallic elements and in quantities of 0.3% to. 10%,preferably 0.3% to 1%, said elements when compared with cerium having asubstantially equal or larger heat of formation during transition intooxides. This effect has been found to be particularly noticeable in thecase of titanium, the use of which brings about the desired decrease inthe press power required to extnide the alloy even when the same has aquantity of tin, for example, incorporated therein. As is disclosed inthe abovementioned U. S. Patent No. 2,660,301, tin or another metal suchas zinc, cadmium or magnesium, is usually employed as ahardness-increasing agent for the alloy and thus for the resulting flintso as to reduce wear and tear of the flint during use to a minimum. Inaddition, other metals'may be employed, for the purpose of reducing therequired press power, such as aluminum, magnesium, calcium, zirconiumand beryllium, either singly or combined one with the other.

The following examples are given for the purpose of demonstrating theinvention:

Example I Misch metalobtained through bastnasite is alloyed with about20.2% iron, 0.5% magnesium and 1% tin, the content of misch metal beingapproximately 78.4%. The hardness. of this misch metal alloy in castform amounts to 89 kg./mm. For the formation through extrusion at: a.temperature of 480- C. a max. press power of 23.0 tons is required. 7

If to the amount of 78.4% of the same misch metal 19.5% iron, 0.5%magnesium, 1% tin, about 0.21% aluminum and about 0.60% titanium areadded, then the hardness of the cast alloy is increased to 97.8 kg./mm.the max. press power forthe formation of the alloy in the. extrusionpress, however, is reduced by about 46%, now amounting to 12.5 tons.

Example 11 If 78.4% misch metal obtained from mon'azite mineral sand isalloyed with 20% iron, 0.6% magnesium and 1% tin, the hardness of thecast alloy thus obtained amounts to 112 kg./mm. and the required max.pressure for the formation of the alloy in the extrusion press amountsto 33' tons. If 0.6% titanium is added to this alloy, then the hardnessof such improved alloy is increased to 116 kg./mm.'- while the max.press power for the formation of the alloy in the extrusion press isdecreased by 42%, namely to 19 tons.

Example III If 74.6% misch metal obtained from b'astnasite is alloyedwith 23.9% iron, 0.5% magnesium and 1% tin, the hardness of theresultant cast alloy amounts to 98.8 kg/mm. and the max. press poweramounts to 25 tons for working the alloy in the extrusion press.

If, however, 74.3% of the same misch metal is alloyed with 23.4% iron,0.5% magnesium, 1% tin, 0.11% aluminum and 0.66% titanium, the hardnessof the resultant alloy is increased to 104 kgjmm. and the max. presspower is reduced by 40%, amounting to 15 tons for working the alloy inthe extrusion press.

Example I V If a misch metal obtained from bastnasite amounting to 70.6%is alloyed with 28% iron, 0.5% magnesium and 0.9% tin, the hardness ofthe cast alloy amounts to 108 kg./mm. and the max. press power to 38tons. If such misch metal amounting to 69.7% is alloyed with 28.1% iron,0.5% magnesium, 1% tin, 0.12% aluminum and 0.7% titanium, the hardnessof the alloy in cast state is increased to kg./mm. the max. press powerbeing reduced for working of the alloy in the extrusion press by about45%, namely, to 21 tons.

The addition of titanium, as well as of other metals as herein set forthwith respect to the misch metal-ironalloy with an iron content from 4.5%to 40% is of extreme practical importance for the manufacture of flintmetal rods to be used for various purposes.

By reducing the max. press power in the extrusion press, practicalworking conditions for this alloy are greatly facilitated, whilemaintenance and durability of the dies and tools of the press areconsiderably simplified and improved.

Although specific embodiments of the invention have been described, itshould be noted that the invention may be realized in modified form andadaptations of the arrangements herein disclosed may be made, as mayreadily occur to persons skilled in the art without constituting adeparture from the spirit and scope of the invention as defined in theobjects and in the appended claims.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. An alloy capable of being extruded at reduced press powers comprisingabout 6 to about 95.5 parts by weight of misch metal, about 4.5 to about40 parts by weight of iron, and about .3 to about 1 part by weight oftitanium having, upon conversion to the oxide, a heat of formation pergram atom of oxygen at least equal to that of cerium.

2. In the process of manufacturing pyrophoric flints by extrusion ofingots of an alloy containing a hardnessincreasing agent, about 60 to95.5 parts by weight of misch metal and about 4.5 to 40 parts by weightof iron, under pressure applied to said ingots at a temperature withinthe range of about 400 C. to about 500 C.; the step of incorporating insaid alloy prior to extrusion of said ingots about 0.3 to about 1 partby weight of a metal having, upon conversion to the oxide thereof, aheat of formation per gram atom of oxygen at least equal to that ofcerium, whereby the press power required to extrude said ingots issubstantially reduced Without adverse effect on the pyrophoric qualitiesof said flints made therefrom.

3. In the process of manufacturing pyrophoric flints by extrusion ofingots of an alloy containing a hardnessincreasing agent, about 60 to95.5 parts by weight of misch metal and about 4.5 to 40 parts by weightof iron, under pressure applied to said ingots at a temperature withinthe range of about 400 C. to about 500 C.; the step of incorporating insaid alloy prior to extrusion of said ingots about 0.3 to about 1 partby weight of titanium and another metal having, upon conversion to theoxide thereof, a heat of formation per gram atom of oxygen at leastequal to that of cerium, whereby the press power required to extrudesaid ingots is substantially reduced without adverse effect on thepyrophoric qualities of said flints made therefrom.

4. The process according to claim 3, being aluminum.

5. The process according to claim 3, being calcium.

6. The process according to claim 3, being beryllium.

7. The process according to claim 3, said other metal being zirconium.

8. The process according to claim 3, being magnesium.

9. In the process of manufacturing pyrophoric flints =by extrusion ofingots of an alloy containing a hardnessincreasing agent, about 78.4parts by weight of misch metal and about 20 parts by weight of iron,under pressure applied to said ingots at a temperature within the rangeof about 400 C. to about 500 C.; the step of incorporating in said alloyprior to extrusion of said ingots about 0.3 to about 1 part by weight oftitanium, whereby the press power required to extrude said ingots issubstantially reduced by about 40 to without adverse eifect on thepyrophoric qualities of said flints made therefrom.

said other metal said other metal said other metal said other metalReferences Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Hackhs Chemical Dictionary, pub. by The Blakiston Co.,Philadelphia, Pa., 3rd ed. 1944; page 541.

1. AN ALLOY CAPABLE OF BEING EXTRUDED AT REDUCED PRESS POWERS COMPRISINGABOUT 60 TO ABOUT 95.5 PARTS BY WEIGHT OF MISCH METAL, ABOUT 4.5 TOABOUT 40 PARTS BY WEIGHT OF IRON, AND ABOUT .3 TO ABOUT 1 PART BY WEIGHTOF TITANIUM HAVING, UPON CONVERSION TO THE OXIDE, A HEAT OF FORMATIONPER GRAM ATOM OF OXYGEN AT LEAST EQUAL TO THAT OF CERIUM.